* Mileage: Most rental companies have a maximum mileage limit that cars are allowed to have before they are sold. The mileage limit for cars rented from major companies is typically between 12,000 and 15,000 miles per year. Once a car reaches the mileage limit, it is either sold or auctioned off.
* Condition: Rental companies also inspect cars regularly to ensure that they are in good condition. Cars that are not in good condition, or that have excessive wear and tear, are usually sold earlier than cars that are in good condition.
* Market demand: If the demand for rental cars is high, rental companies may keep cars for a shorter period of time in order to capitalize on the high demand. Conversely, if the demand for rental cars is low, rental companies may keep cars for a longer period of time in order to avoid having too much inventory.
Ultimately, the decision of how long to keep a rental car is a business decision that is made by each individual rental company.
